Process fob the production of a



' 'Reissued May 30, 1939 rnocsss r01; THE PRODUCTION COLORED OF A SOUNDFILM' Bla'Gaspar, Brussels, Belgium Original Nb. 2,025,658,

dated December 24, 1935,

Serial No. 657,925, February 21, 1933. Application for reissue March 28, 1939, Serial No. 264,665. In Germany February 19, 1931 1Claim.

Processes are already knownin which colored sound films are reproduced, but their production is extraordinarily complicated. Moreover, ithas hitherto been diflicult to combine a colored pic- 5 ture and a black'sound strip or track laid in different emulsions. The present process enables a colored sound picture and a black-and-white sound strip to be combined in onefilrn strip in a simple and faultless manner. Several processes are known (see, for example, my prior Patents Nos. 1,956,122, 1,956,017, 1,985,344, 2,020,775, and 2,071,688, in which there is employed a silver halide material comprising a plurality of layers and having dyestuffs or dyestuif-forming substances incorporated therein, these substances being, after the production of the silver image in the said layers, converted into colored images. In carrying out the present invention in its preferred forms I employ the materials and the. processes set out in my said prior patents The said processes consist in forming the dyestufi image in a manner dependent upon the silver image by local formation of the dyestuff from dyestufi forming substances or by locally discharging the diffusely distributed dyestufi or dyestufi-forming substance at the image or nonimage parts in proportion to the metallic deposit present, whereupon finally there is discharged the silver leaving a pure dyestuii.

The use of light-sensitive films having the requisite color substances already incorporated therein oflers considerable advantages overthe other known process of coloring the film subsequent to the formation of the silver image, because a much greater degree of certainty is obtained that the color substances are evenly distributed and, furthermore, the production of the colored image is materially facilitated. The term color substances as employed in this specification refers to all substances which are capable of supplying dyestufi images, i. e., both finished dyestufi's as well as dyestufl formers.

Now although the use of layers which already contain color substances prior to theexposure offers particular advantages in the production of colored images, certain difficulties have been encountered in producing a satisfactory sound record, as with similar treatment of the visual and sound record portions of a film the sound record substances at an initial stage. The drawing isa 5 ess.

would also be a colored one, and particular measures are necessary to obtain a black and white, sound record in a film which contains the color flow sheet diagrammatically illustrating the proc- In order to obtain a well-defined sound strip, it is necessary that it should be black-and-white, becausethe blackening curve is very difllcult to reproduce free from distortion with a colored sound image; this difllcuity occurs especially in the case of the so-cailed intensity process. For this purpose, according to the invention, only the picture portion of the film strip is converted into a colored picture whilst, at the position of the sound track, the conversion of the silver image into the dyestufi' image is omitted. According to the invention, this is effected by the employment of a resist that prevents thepenetration by chemical substances which would eiiect the con-' version of the silver image into the dye image. This resist may consist of, for example, a layer of alcoholic varnish or of a fatty substance such as, for example, tallow or wax. It is. in addition possible to employ purely chemically active resist agents; for example, an oxidizing bath is employed for converting the silver picture into a dyestuff picture. In this case, a resist may be employed which consists of a thickening agente. g., gum arabic and sodium hydrosulplflte, i. e., an agent that acts in a chemically opposite manner, in this case a reducing agent. Obviously, other chemically active resist agents may be em-' played for attaining the same object, but it is also possible to re-convert the already formed dyestufl: image (consisting of dyestufl and silver salt) into a silver image with'previous. subsequent or simultaneous destruction of the'dyestuir if the following is applied at the position of the sound strip:-sodium hydrosulphite alone or with amidol. It is possible in the case of a2colored sound picture at the place of the sound record which consists of a black silver band, to allow the dyestufl. to remain'by means of a local resist in all part of the layers, by protecting it before its destruction, or the followingmethod may bev adopted. The dyestuff' is destroyed in, say, two layers so that only the third remains colored. The color that is chosen in the particular case is immaterialand only depends on'the nature of the sensitivity of the,.Photo-electric cell. A color may. be selected which is'suitable for the employment of invisible rays such as the ultra-violet and the infra-red rays,

What I claim and desire to secure by Letters Patent of the United States is:

The method oi producing color kinematographic sound films wherein the picture is a color picture and wherein the sound record'is a metallic silver image, which consists in forming in a pre-dyed photographic light-sensitive silver halide emulsion layer a developed and fixed silver image constituting a sound record and a silver image constituting a picture record, treating said records with an agent-which locally destroys the dyestufl' to convert each 01' the said records into -acolor image, converting the metallic silver in the visual and sound records into silver'salt,

21,090 i treatingthesoundreoordonlyvvithareducina substance to reoonvert the silver salt into metallic silver, and thereatter dissolving the silver salt 

